Epidemiology of Autism Spectrum Disorders: A Multifactorial Model for Populations in Transition

Background: Autism Spectrum Disorders (ASD) are a group of developmental disabilities characterized by impairments in social communication, restricted areas of interest, and repetitive and stereotyped patterns of behavior. Symptoms typically are apparent by the age of 3 years.

Objective: To determine the prevalence of ASD among children of the largest of 4 health maintenance organizations in Israel.

Methods: Point prevalence and diagnostic trends of ASD over the past 18 years were examined over a wide geographical area of central Israel, encompassing a database of 331,169 children, age 3-18 years. Special importance was attached to statistics from different religious and ethno-cultural groups as potentially reflecting discrepancies in diagnosis, reporting, and possibly environmentally-related trigger factors in the causality of an essentially genetically determined syndrome.

Results: Overall prevalence was 0.004 (1/250 live births), well below firgures from other similar studies abroad and in Israel. Prevalence figures for the ultra-orthodox Jewish community were the lowest (0.0022), when compared with the general population and Israeli Arabs (0.0033). Time trends indicated a surge of ASD among Israeli Arabs and Ethiopian Jews between the years 2004 and 2015, in contrast with a general flattening for the ultra-orthodox community (p<0.01).

Conclusions: Results indicated that besides discrepancies in diagnosis and reporting factors, there exists a possible relation between clinical expression of an ASD genetic predisposition and the socioeconomic/ cultural environmental factors at work in impacting on the epigenetics in the causality of autism. Our prevalence rates are currently lower than those for ASD in Europe and the USA. The results should be of special interest to planners of health and educational services for the handicapped in countries with minorities or immigrant groups in social transition.